Current remote mobile health monitoring uses peripheral devices that connect to a mobile phone or Internet via a hub. A smartphone case system, designated ?Vital-Case System? (VCS), has been developed that allows repeatable use of cell phone biosensors to obtain accurate vital signs measurements of temperature, HR, and SpO2, and electrodes embedded in the case itself allow electrocardiogram (ECG) reading (Maxim Integrated, CA). Direct use of smartphone embedded biosensors enabled by a case, which also enables ECG reading is highly novel and has far reaching implications and may be of substantial use in making remote vital sign monitoring available to low resource settings. This proposal expands the R01MH110057 ?A Novel Edible Sensor System to Characterize Antiretroviral Therapy Adherence? to validate vital sign measurement via VCS in HIV-infected and high-risk HIV-uninfected populations. The research proposal also includes the addition of an exploratory intervention study arm to the parent R01 MH110057 to explore DHFS acceptability to hospitalized HIV-infected subjects and its utility to support their medication adherence post hospital discharge. Aim 1: Evaluate the validity, use and acceptability of the VCS. We will conduct a single arm within-subject design intervention using primarily participants of R01 MH-110057. We will determine and validate the accuracy of the VCS vital sign measurements compared to that of commercially available ?gold? standard Welch Allyn instruments in participants in the clinic, outpatient and home setting. A sub-set of 40 participants will be recruited to use the VCS independently at home, to obtain vital sign measurements for the duration of their participation in the parent R01 study. In addition, 20 participants will be recruited during Sleep Laboratory testing of Obstructive Sleep Apnea (OSA) to validate measurements of SpO2 and HR in an outpatient setting of low SpO2. The primary end point will be to determine and validate the inter- and intra-machine accuracy of VCS and the ?gold? standard Welch Allyn devices by comparing vital signs in the same participant. Aim 2: Explore the acceptability and utility of the DHFS use in hospitalized HIV infected participants post- hospital discharge We will conduct an intervention study on 30 hospitalized HIV infected Subjects with detectable plasma HIV RNA. Subjects will be enrolled into a 16 week intervention study using the DHFS whilst still in hospital. Upon discharge, participants will continue use of DHFS. Longitudinal patterns of ARV medication ingestion will be captured by the DHFS for the duration of the study and the system will be used to derive an accurate measure of adherence. An adaptive design will be followed: any Subject under 90% ARV adherence receive adherence support based on daily DHFS generated ingestion data. The primary end points will be the number of doses ingested captured by the DHFS over the number of doses prescribed in this population.